Quern



S. BJERRE QUERN Feb. 4, 1930.

2 sheets-snm 1 Filed Jima 9. 1928 S. BJERRE Feb. 4, 1930.

QUEEN v 2 Sheets-Sheet 2 Filed June 9. 1928 Patented Feb. 4, 1930y tienePATENT orrlcr.

SILIAM BJERRE, OF SKIVE, DENMARK QUEEN Application filed .Tune 9, 1928.Serial No. 284,093.

rlhe present invention relates to a quern of the kind comprising arotary and a nonrotary grinding body between whichthe substance to beground is introduced, the said -substance being, perhaps, grain, cacao,coffeek or some other similarl subst-ance.

In quernsy of this nature it has previously been proposed to journal thegrinding bodies in such a mannerthat excessive loading of vl the quernkwill cause one of the grinding 'bodies to be displaced away from theother one. f

This relative displacement of the grinding bodies is effected either bythe material to be ground between the grinding surfaces pushing therotary grinding body away from the non-rotary grinding body and, at thesame time, compressing a spring which holds the' t rotary grinding bodyin Contact with the material tovbe ground, or by the friction betweenthe grinding bodies and the material to be Ojround, which friction ishighly increasecllby overload on the quern and causes a rotation of thenon-rotary grinding body, whereby the *latter moves axially away fromthe rotary grinding body. In the last mentioned caseV the rotation ofthe non-rotary grinding body has alsobeen utilized to reducevthesupplyof material to thequern by displacing the feeding device for 'thematerial to be ground. y v

vThese heretofore known querns, however, and themethods used forregulating .the same `suffer from various drawbacks. Then the reliefofthe quernduring an overload is effected by displacement of the runner,this displacement as a rule causes compression of Vthe spring `pressingthe runner against the material to be ground. This compression. however,increases the spring power and, consequently, the pressure at which thespring presses the rotary grinding body against the material.l lf-theoverload is due for instance to al hard foreign body entering-betweenthe grinding surfaces, 4then the displacement fof the rotar] grindingbody will consequent-ly cause the pressure between the said foreign bodyand the grinding surfacesA to be increased, the consequence of which maybe a `total destruction of the grindingsurfaces.

r... ud

If the above mentioned rotation of the nonrotary grinding body isutilized to regulate the load, then the said body must be adapted torotate as well as to be displaced in axial direction,and according tocircumstancesv the construction of the quern may consequently becomplicated and expensive.

One of the objects of the present invention is to produce a quern bywhich, in case of overloading, a relief is effected automatically by anaxial relative displacement of the two grinding bodies, without thepressure between the latter and the material be ing thereby increased,which advantage is attained by journalling the quern housing in such amanner that the said housing, when the friction between the grindingbodies and the material to be ground exceeds a certain permissiblevalue, is swung through a larger or smaller angle in the direction 'ofrotation of the quern shaft, whereby a displacement of the grindingsurfaces relatively to one another is effected.

Another object of the invention is to utilize the said rotation of thequern housing for reducing the supply of grain to the quern, the saidreduction being attained by arranging a tappet on the quern housing toengage a shaking tray, which is kept in motion by means actuated by thequern shaft and which serves to supply the material to the feedingaperture of the quern housing, and to push the said tray away from thesaid means.

A further object of the present invention is to employ means by whichthe distance between the grindingsurfaces may be adjusted to any desiredextent, in such a manner that the degree of fineness obtained by thegrinding treatment may always be determined at will.

Still another object of the invention is the provision of means by whichthe grinding bodies may be moved manually away from one another by arotation of the quern housing by hand. n

Finally the invention relates to means by which the quern housing isattached in such a manner to a frame in which it is journalled thatlthev quern housing, when actuated by the friction between the grindingsurfaces, 100

will not rotate until the load on the quern and, hence, the saidfriction, has exceeded a certain limit.

Still another object of the invention is the use of means by which thegrinding bodies may be `moved manually away from one another by arotation of the quern housing by hand. y

Further details of the invention will appearfrom the followingdescription of the constructions shown on the drawing.

Fig. 1 is a central vertical section of a quern constructed according tothe invention,

Fig. 2 is an end view of the quern, with parts in section, and

Fig. 3 is a section of the quern along the line B-B in Fig. 2, n

Figs. 4 and 5 are views corresponding to Figs. 1 and 2, but showinganother construction of the quern,

Figs. 6 and 7 represent a detail of the construction shown in Figs. 1and 2, in cross-section and in longitudinal section, respectively, and

Fig. 8 is a diagrammatic viewof another construction of the quern, inside elevation.

6 on the quern case.

1V is a frame shaped as a hollow post, and 2 is a mainly cylindricalquern housing formed on one side with a projecting hollow`trun nion 3 bywhich the housing 2, referred to in the following as the quern case, isjournalled in the frame 1.

In the quern case there is fixed a mainly annular grinding body 4 with acentral cavity 5 communicating with a feeding channel 7 is a shaft whichis journalled in the trunnion 3, in ball bearings' 8 inserted in thesame. One end of the shaft7 extends into the quern case and supportsthere a grinding body 9 disposed opposite the grinding body 4. 10 is ahelical spring inserted in the trunnion 3 so that it encircles a portionof the shaft 7 and exerts an axial resilient pressure on the latter,which pressure maintains the grinding body 9 in resilient contact withthe material contained between the grinding bodies. One end of thespring l() rests against one of the ball bearings 8 in which the shaft 7is free to move axially, and the other end of the spring rests againstan eccentric 11 which is fastened on said shaft and the function ofwhich will be described more fully later on. 12 is a belt pulley fixedon the shaft 7 beyond the end of the trunnion 3 and serving to rotatethe shaft 7 and the grinding body 9.

The material to be ground in the quern is introduced into a hopper 13supported by brackets 14, Fig. 2, which are attached to the frame 1. Thehopper 13 dischargesr at vlboty tom into a so-called shaking tray 15,one end of which is pivoted about a pin 16 on the hopper, whilevv theother end projects-out to, andoverlies, the feed channel 6 on the querncase.

17 is a rod which extends out through the hollow frame 1 and is guidedat both ends by suitable holes in the same, one end of the said rodresting against the periphery of the eccentric disc 11, while the otherend rests vagainst the bottom of the shaking tray 15 as shown by Fig. 1.

0n the end facing the quern, the channel 6 is fitted with an arcuateprojection 18.Y

Between the latter and a flan-ge 19 on the bottom portion ofthe frame 1there is inserted a resilient member consisting of a. rod 2O -the upperend of which is threaded and rests against the bottom side of theprojection 13, while the` lower end-of the rod is adapted to slide in aconical guiding block 21, the bottom end of which is journalled intheflange 19 by means of a pin 22. Around the rod 20 and the guiding block21 there is inserted a helical spring'23 the bottom end of which restsagainst a flange 24 on the gui'dingblock 21 and the top end of whichrests against a cupped washer 25 which is inserted on the top end of therod 21 and is held in position against the pressure of the spring 2O bymeans of a nut 26. By tightening up this nut it bev comes practicable,without altering the length of the entire device consisting of the rod2O,V

the spring 23 and the guiding block V21, to regulate the spring pressureand, thereby, the force with which the spring tends to turn the querncase in the direction indicated by the arrow in Fig. 2 which is oppositethe direction of rotation of the grinding body 9.

The tension of the spring 23 is adjusted in such a manner that the querncase will remain in the position shown in Fig. 2 as long as the quern isin use without being overloaded, since the power of the spring 23 willcounter-k balance the torsional moment due to the friction between thegrinding bodiesand tending to rotate the quern case in a directionopposite the direction of the arrow in Fig. 2.

The ball bearing 3i nearest to the rotary grinding body 9 rests on'oneside against the eccentric sleeve 11 and on the other sidel against aring 27 inserted on the 'shaft 7, see

Figs. 1 and 3. The sideof the ring 27 facing'the grinding body 9 restskagainst the slotted central portion 28 of an arm 29 which is disposedinside `ofa bore y30 on the side of the quern case facing theframe 1,and is attached to the quern case at both ends rby'means of a bolt 31,Fig.Y 3, which passes through the quern case and through a washer Y 32disposed on the outside of the latter; a hand wheel 33, Fig. 3, beingprovided on the bolt 31 outside ofthe said washer. Both ends of the arm29'are attached to the quernkr vcase in the above `described manner, sothat by. tightening up the handkwheels 33, one of which is shown in Fig.2 and the otherone in Fig. 3, the central portion 28 of the arm 29extending transversely through slots 34 in the trunnion 3, but outsideof the sha-ft 7,

kmay be pressed more-or less. forcibly against 31-mayjserve to adjustthe distance between thegrinding surfaces 35 and 36, rrespectively/,onthe two grinding bodies 4 and 9, since fa rotation of the hand ywheels33 will cause a displacement of the ring 27 towards the spring 10 and,thereby, a compression of the latter simultaneously with anaXialdisplace- .ment of the shaft 7 and the grinding body 9 away. fromthe grinding body 4. In this manner it becomes practicable, byadjustment of the hand wheels 33, to attain any desired distance betweenthe grinding surfaces 35 `and 36 and, hence', any desired degree offinenessv of the ground material.

To a lug 37 on one sidef of the frame 1 therey is attached, by means ofa screw 38,

a curved rail 39, the lower end of which is fork-shaped and passesthrough a recess 40, Figs. 3, 6 vand 7, in the washer 32. providedbetween thequern case and one of the hand wheelsk 33.l f

The end ofthe recess 40 facing the rail 39 has a sloping bottom face 41,and the rail 39 is fitted with a corresponding sloping face W42, Fig. 3.

lThe quern described acts in the following manner: When the shaft7 isrotated by means of the pulley 12, the grinding body 9 isthereby causedto rotate, and the eccenftric sleeve 11 on said shaft moves the rodv 17up and down and, consequently, alternately lifts and lowers theshakingtray 15, thusy causing the latterto oscillate about the pin 16-The material fed into the hopper 13 falls vtherefrom upon the shakingtray and, actuated by the motions ofthe tray, travels longitudinallythrough the said tray and f drops down into the channel 6, whence it fpasses by way-of the aperture 5 in the grinding body 4, to the grindingsurfaces 35 and 36. After being ground the material leaves the quern byway of a discharge spout 43 on the side vof the quern case, whenceit is-v caught in a .box 44 .serving to'store it and to support the post 1.The material may be directed from the spout 43 to the box k.44 by anyysuitable means such as hose, a bottomle'ss bag or the like, one end ofwhich is joined lto the spout 43 while the other endV is inserted intothe boX 44 by way of Van aperture (not shown) in the same.

The limits of the vpresent invention will not be' transgressed byomitting the box -44 and by discharging the' material from the spout 43into any other devices ofk known nature, such as bags,.boxes, pails andthe like. As shown by Figs. 1 and 2 the quern castI is split and itskmembers joined together by meansV of screws 46. The grinding body 4 isattached to the quern case by means of i a suitable number of screws 47which are screwed eitherv directly into the grinding body for instancebymore grain being fed into the quern than the latter is able to grind, orby some foreign body penetrating between the grinding surfaces, then thefriction produced between the material and the rotary grinding body,which friction yreacts on the grinding body 4 fixed to the quern case,will cause the latter, when actuated by this friction, to rotate in adirection opposite the arrow in Fig. 2, whereby the spring y23 will becompressed.

This rotation will bring the sloping face 41 of the recess 40 in thewasher' 32 towards the sloping face 42 on the rail 39 which will causethe washer 32 and, hence, the bolt 31 `and the end of the arm 39connected thereto,

to move in the direction indicated by the arrow in Figs. l and 3,whereby the central body 9 back into the position corresponding to itsoriginal adjustment. Provided that the overloading is due to excessivefilling of the quern channel with material it will be suitable, in caseof overload, to reduce the supply of grain to the channel. Thisreduction is attained by the provision, on the periphery of the querncase, of a cam y49 (Fig.

2) the wedge-shaped face y50 of which projects down below a lug 51 onthe under side of the shaking tray. When the querncase is rotated inconsequence ofy an overload, the sloping face 50 of the, cam 49 willstrike the lug 51 from below and lift the shaking tray 15` so far thatit will clear the top end of the rod 17, which latter cannot thenkactuate the shaking tray any more. The tray will therefore becomestationary, and the passage of material-along the tray and,consequently, the supply of'material into the feeding channel willtherefore bek reduced very considerably.

On a boss 52 on the side of the quern case there is pivoted by means ofa pin 53, Figs. 2 and 3,a leverfcomprising a handle portion 54 and ahead or cam portion 55, the periphery of rwhich rests against theframe 1. p

By rotation of the lever about the pin 53, in such a manner that theperiphery of the cam 55 is forcedV to slide against the frame 1, thequern case may be turned by hand against thev action of the' spring 23wherebyk the cri grinding bodies are removed "from one 'another in theabove described manner.

tion of the present quern in which the frame of the quernfcase, insteadof providing one single bearing for journalling the quern case,providestwo bearings 60 and 61, respectively, serving to support thesame. The quern case which, in this construction also, is mainlycylindrical, with a dischargespout 43 projecting from the periphery, isfitted, at bothv vend faces, with trunnions 63, 64 journalled each inone of the bearings 60aiid 61, in such a manner that the quern case mayrotatein said bearings. VAny not intended rotation of f the quern caseis prevented by means of two 'springs 76 and 66, Fig. 5, which are eachpushed over an end of a lug 67 provided on the 'inner side'of one ofthebearings 61, and a stop` 68 on the quern case in close proximity withthe said lug. The outer end ofeach spring rests against the Washer 69which is attached to the bolt ends by means of nuts 70, and the innerends of the springs 76 and 66 bear against the stop 68 and the lug 67,respectively, suitable pressure blocks 71 being inserted between thelatter and the spring ends.

As appears from Fig. 5, the bore in the lug 67 through which the bolt 72passes is flaring, so that said bolt may oscillate .in the lug 67 whenthe quern case is rotated in the direction indicated by the arrow in Fig.' '5. yThe quern shaft 7 is journalled, in both of the truiinions 63and 64,r in ball bearings 65, one of which is provided in each of thesaid trunnions. The springl 10 pressing the. rotary grinding bodyagainst the material'between the grinding surfaces is disposed inside ofthe trunnion 63 and encircles the portion of the shaft 7 which issituated between the grinding body 9 and the ball bearing 65 in the saidtrunnion. n

Thevother end of the quern shaft projects into the trunnion 64 and issupported there as mentioned aboveby a ball bearing 65, and the shaftitself supports the eccentric sleeve 11 serving to move the operatingrod 17 of the shaking tray 15. The last mentioned end of the shaft 7 isfurther provided with a bore is inserted. This ball receives thepressure e 'journalled in the fixed frame' of the quern,

from the end of a threaded spindle 74 which is screwed into a nut 75and, outside of the said nut supports a hand wheel 77. The nutV positepins 78, a ring encircling the outer end'of the trunni'on V64a1`idpivotedmon a pin l *i 81 in the lug 82 on the bearing 61. The ring i' 80isfattached, at one point of its periphery, to the pin'64 by means of ascrew 83. 84'is a wing nut serving as check-nut for the nut 7 5%? andsecuring the'spindle 74'iinmovably in the latter. v f c Y ln'thisconstruction also, the shaking tray exactly to the cam member 50 in Fig.2, but i 'is here attached to a collar 86 which ylimits lthe supplyopening 6.

The top face of the 15 is pivoted about a pin 16 on the` feedingliopperl, the supporting Vbrackets 14 of" tappet^85 rests against a'projection 51V on the bottom side of the shaking tray 15.

I 'Byloosening the nut 84 and turning the hand wheel 77, the'shaft 7maybe displaced longitudinally against the action vof the spring 16,whereby the grinding body 9 will vbe moved away from the grinding body4,` so that it will be practicable toL adjust the i grinding bodies toany desired clearance An automatic adgustinent of the Vload on ,latterwill rotate'in'th'e direction indicated by the arrow in Fig. 5, and thesprings 66 and 76 will thereby be compressed. Due to this rotation vthepin 78 on the nut 7 5 will* move upward in. the sloping slot 7 9, asindithe quei-nis effected in the following nianj cated by the arrow inFig. 4, and thereby thek vnut 75 and consequently the threaded spindle74 will be pushed inward into the trunnion 64, in such anianner lthatthe shaft 7 will be displaced and will pull the grind- Y ing body 9 awayfrom the grinding body 4.

The rotation of the quern case will, at `the same time, cause thetappet85 tol lift the shaking tray in suoli a manner that the latter ceases tobe actuated by the rod 17 during as mentioned above.

If preferred, there ymay be used, instead ofy the spring devicecomprising parts 66-72,

a devicelike the one shown in Figs. 1-'3 for preventing the rotation ofthe quernt case,

and inA general the above described "details of the first constructionmaybe Vapplied directly Vto the modified V'ccinstru'ctiong `withoutthescope fof vthe continued rotation ofthe shaft 7, where- `by the supplyofgrain willbegreatly reduced K4iis e In both constructions the quern caseis and the quern shaft is Vjournalled in the quern`V "ies y journal theshaft 7 in the bearings90 ona base or bed 91, there being then insertedbetween the quern case 2, and the base 91 aresilient device 92of-anysuitable construction tary grinding body 9" as indicated by the arrow inF ig. 8. The` spring 10 may be inyserted, forinstance, between a ring 93fixed on the shaft 7 and the ring 27V resting against the centralportion 28 l(Fig. 1) ofthe arm 29.

f5"3 In the construction shownin Fig. 8 the guidingrails, 39may bedisposed'at any suitable ypoint ofthe quern base 91.

Having now particularly described 'and A ascertained the naturejof mysaid invention and iny what manner the same is to be per-` formed,Ideclare that what I claimlis 1. A: quern comprising a quern shaft, a.

quernicase arrangedto -revolve about the axis Hof the quern, agrindingbody attached tor 25' the quern case, a grinding body facing thefirst .one aand attached to the quern shaft to 'be rotated by thefsame,means to prevent4 rotationvr of the quern' case untilthe load on n thequernfexceeds a permissible limit and to,

30"'al1owthequern'case to perform a rotary v.motion in the direction ofmotion ofthe quern.y shaft consequent Aupon the' friction which,y

during an overload arises between the mate-A .-rialto be ground and thegrinding'bodies,

and means wherebyV thequern case,on beingv rotated, spaces the grindingbodies fromy each other. n Y 1 2.1A querny comprising a quern shaft', a

-quern case arranged to revolve about the axis 40'"of the quern,agrindingbody attached to the quern case, ay grinding body facingthefirst one and vattached to the quern shaft to be rotated bythe same,a-,feeding device disposed above a. supply openingv in the quernv case,

"means *operated` by the quernshaft during itsrotation for oscillatingthe feeding device, means` to prevent rotation of the-quern caseuntilthe load on the quern exceeds a A .permissible' limit andto allow vthequern case v""t0'fperform a rotary motion in the direction of motion ofthe quern shaft-consequentupon thee vf riction which, 'during anoverload, arises between the material to be ground .f @and the grindingbodies, means whereby the .55"quern case, on being rotated, )spaces thegrinding bodies from each other, andmeansf whereby the quern casesimultaneously effects Y such a relative displacement betweenl thefeeding device andthe means for oscillating it that the vsupply ofmaterial fed to the quern case will be reduced.l

` 3. A quern comprising a quern case, a quern shaft journalled in thequern case, a frame iny which the quernY case -is journalled co-axially5 with the quern shaft, a grinding body at- In such case the rotation.

tachedy to the quern case, a grinding body facing .the first one andattached to the quern shaft to be rotated ,by the same, a feeding devicedisposed above a supply opening in the quern case, means operated by thequern shaft during itsv rotation for oscillating the feeding device,means to prevent rotation of the quern case until. the load on the quernexceeds a permissible limit and to allow the quern case to perform arotary motion in the direction of` motion of the quern shaft consequent.upon the friction which, during an overload arises between the materialto be ground and the grinding bodies, means whereby the quernv case, onbeing rotated,

spaces the grinding bodies from each other, L

and means whereby the quern case simultaneously effects such a relativedisplacement betweenthe feeding means for oscillating it that the supplyof material fed to kthe quern case will beVv reduced.

4. A quern comprising a quern case, a quern 'shaft journalled in thequern case, a frame in which the quern case is journalled co-axiallywith they quern shaft, a grinding body at-4 tached to the quern case, agrinding body p facing the first one and attached to the quern.

shaft to be rotated by thefsame, a feeding device which is disposedabove a supply opening inthe quern casey and directs material thereto,'means for actuating said feeding device, means connecting the saidframe to thequern caseand preventing rotation'of the latter until the.load onthe quern exceeds la permissible limit, said means allowingv thequern case to perform a'rotarymotion inl the` direction of motion'of thequern shaft consequent upon the friction which, during an overload,arises between the material to be ground and the grinding bodies, meanswhereby the quern case, on being rotated.v spaces the grinding bodiesfrom one another, y

and means whereby the quern case simultaneously' effects such a relativedisplacement between the feedingcdevice and itsy actuating means thatthe supply of material fed to the quern case will be reduced.

5. A quern comprising a quern case, a quern shaft j ournalled in thequern case, a frame in which the latter is journalled, a grinding bodyattached in the quern case, a grinding body attached, opposite the firstone, to the `quern shaft to be rotated by the same, means for adjustingthe distance between the grinding surfaces on theftwo grinding bodies, afeeding device whichl is disposed above a supply opening in the querncase and directs material thereto, means for actuating `said feedingdevice, means connecting the said frame to the quern case and preventingrotation of the latterk until the load on the quern exceeds apermissible limit, said means allowing the quern case to perform arotary motion in the direction of' motion of the quern shaft consequentupon the friction which, during an overload, larises between thematerial to be ground and the grinding bodies',-means whereby Ythe querncase,l on beingl rotated, spaces the grinding bodies from each other,and means wherebyl the quern case simultaneously effects sucha relativedisplacement between the feeding device and its actuating means that thesupply of material fed to the quern case will be reduced.

6. A quern comprising a quern case, a que-rn shaft journalled in thequern case, a framein which the'quern case is journalled co-arially withthe quern shaft, va grinding body attached to the quern case, a grindingbody attached, opposite the first one,'to the quern shaft to be rotatedby the saine," a spring maintaining the rotary grinding body pressedagainst the Lmaterial to be ground-between the grinding surfaces of thetwo bodies, means foradjusting the distance ,betweenthe two grindingsurfaces against the` pressure of the said spring, a feeding devicekwhichis disposed above asupply opening in the quern caseaii'd directsmaterial thereto, meansl for actuating said feeding device, meansconnectingthesaid frame to the 'quernfcase and preventing rotation ofthek quern case until'nthe loadoii ithe yquern exceeds a permissib-lelimit,

saidY means allowing the quern case to performV arotary motion in thedirection of Ymotion of the quern shaft consequent upon'the frictionwhich,`during an overload, arises between n the materialto be groundandV the grinding' bodies,"meansfwhereby the quern case, on beingrotated, pspaces the grindingbo'dies from each other, and means by whichthe quern case simultaneously eiectsf such' aV relative fdisplacementVVbetween thefeeding device and itsl actuating rmeans vthat the supplyof material fed to the quern case will be reduced.

7'.' A quern'comprising a quern case, a quern shaft jouri'ialled intheque'rn case, av framein which' the quern ca'seis journalledi, resilientmeans connecting the quern case with the frame and vpreventing rotationof the quern case so longfas the load on the quern does noty exceed acertain limit, aA grinding body l.fined in the quern case, a grindingbody attached toV thequern shaft to be rotated by the same,

a spring maintaining the last mentionedr8. `Aoluern comprising a querncase, a quern' shaftfjournalled in the quern case, frame in` which thequern case is journalled, resilient means connecting, the quern casewithr the frame and preventing rotation ofthe'quern case so long as theloaden thequern does not exceed a certain limit,`a grinding body whichis attachedto thel uern case a Grindinobod f attached to the kquernyshaft'and rotated'by the same, a' spring maintaining the last men-vtioned grinding body pressed resiliently against the material to beground, means to Y adjust the distance between the grinding sur-V facesagainst the pressure of the said spring,

said adjusting means beingactuated b y the quern case, when the latterrotates, in such; a manner that the said means push onegrind-V ing bodyaway from'the other one, whereby the quern is relieved; a'feedingdevice, means moved bythe quern shaft and imparting an oscillatorymotion to the feeding device, and

a ycam on the quern .case which, during a rotation of the quern case,moves the feeding device away from its actuatingineans, whereby thesupply offgrain fed tothe'quern case will be reduced. Y H V i i 9. Aquern comprising a quern case,'aquerny shaft journalled in thequerncase, a y.frame in which the quern case is Journalled, resilientmeans connecting the quern case to the frame andvcoim'teracting.afrotation of said case, a grinding body which isattached' to the quern case, a grinding bodyy attached tothe `quernshaft andi rotated by the same, a spring which maintains the rotarygrinding body pressed resiliently against Vthe material to be groundvlb'ctween'the grinding surfaces, a body 'atl tached a'djustably tothequern case and serving to transmit the pressure of the said spring tothe quernshaft, a stop for the said body providedon the frame of thequern case; said body and said stop havingcoacting sloping sof Y contactysurfaces to cause the s'aid'body and,

hence, the quern shaft and the grinding ,body

attached thereto to move vaxially kwhentheY quern case, by itsrotatioin,moves the saidbody along the/said stop; a feeding device,

means actuated bythe quernfshaft for imwV parting an oscillatory motionto the feeding device, and a cani on'the quern .case which, when theAlatter is rotated in the direction of lrotation of the quern shaft,pushes` thelfeed'- ingdevice away from the means serving to oscillateitwhereby the supply of grain fed to the quern case will' bereduced.

l0. A quern comprising a quern case, a

quern shaftjournalled inthe quern case,a

frame in which the quern case is journalled, resilient meansconnectingthe quern case to Vthe frame and counteracting a rotation of said case,a grinding body whichv is attached toy iis,

the quern case, a grinding body attached to v the quern .shaft androtated the same, a spring which maintains the rotary grinding bodypressed resiliently against the material. to be ground betweenthe'gnin'ding surfaces,

'iscA a body attached adjustably to the quern case and servingtotransmit the pressure of the said spring to the quern shaft, a stopfor the said body provided on the frame of the quernr '5 case; said bodyand said stop having coacting vsloping surfaces to cause the said bodyand,

hence, the quern shaft and the grinding body attached thereto to moveaxially when the quern case, by its rotation, moves the said body alongthe said stop; a feeding device, means actuated bythe quern shaft forimparting an oscillatory motion to the feeding device, a cam on thequern case which, when the latter is rotated in the direction ofrotation yof the quern shaft, pushes the feeding device away from themeans serving to oscillateit, whereby the supply of grain fed to thequern case will be reduced, and an arm pivoted to the quern case, oneend of said armresting against the frame of the quern case in such amanner that the arm, when rotated, forces ythe ,quern case lto rotate inthe frame, whereby the grinding bodies are moved away from each other.

11. A quern comprisingl a quern case,fa quern shaft journalled in thequern case, a frame nwhich the quern case is journalled,

, resilient `means connecting the quern case to p theframe andcounteracting a'rotation of the 3oj-sa1d case, a grinding body which isattached yto the quern case, a grinding body attached to ,the quernshaft and rotated by the same, a spring which maintains the rotarygrinding body pressed resiliently against the material Y to be groundbetween the grindingsurfaces, a body attached adjustably to the querncase and'serving to transmit the pressure of the said spring to thequern shaft, a stop for the said body provided on the frame ofthe querncase ,sa-id body and said stop having coacting sloping Contact surfacesto cause the said body and, hence, the querny shaft and the grindingbody attached thereto to move axially when the quern case, byvitsrotation, moves the said body along the said stop, a box to receive theground material and to support the frame, a feeding device, meansactuated by the quern shaft for imparting an oscillatory motion to f thefeeding device, arcam on the quern case which, whenv the lattery isrotated in the direction of rotation of the quern shaft pushesthe'feeding device away from the means serving tov oscillate it, wherebythe supply of grain fed to the quern case will be reduced, and an armpivoted to the quern case, one end of said arm resting against the frameof the quern case in suchl a inanner that the arm, when rotated, forcesthe quern case to rotate in the frame, whereby the grinding bodies aremoved away from each other.

12. A quern comprising a quern case, aV

and counteracting a rotation of the latter, a

quern shaft journalled in the said trunnion and projecting into thequern case, a grinding body attached to the quern shaft inside oi thequern case, agrinding body attached to the quern case and facing thefirst mentioned grinding body, a shoulder on the quern shaft, an'adjustable arm provided on the quern case, a spring provided in thetiunnion on the quern case and encircling the quern shaft and adapted toexert .an axial resilient pressure which maintains said shoulder incontact with said adjustable arm, so that an adjustment of said armcauses the quern shaft to be displaced axially, whereby the spacebetween the grinding bodies is varied, a stop attached to the said postand resting against one end of the said arm, means whereby the other endof the said arm may be adjusted manually rela tively to the quern caseand thereby caused to movein such a manner that it displaces the quernshaftaxially, a shaking tray pivoted to the frame and set intooscillating motion by action of the quern shaft, a cam on the peripheryof the quern case adapted to push the shaking tray away fromthe membersactuating the same when the quern case is rotated, and an arm pivoted tothe quern case and having one end resting against the post, in such kamanner that on rotation of the arm, its said end forces the pivot of thearm on the quern case to `move away from the post and, consequently, thequern case to rotate.

In testimony whereof he aftixes his signature, f

SILIAM BJERRE.

